ddeboer/data-import — pull request #48 by ddeboer (2014-01-09 20:59:32+00:00)
Title: Simplify source

* This PR gets rid of the `SourceInterface`, as both our file readers (CsvReader and ExcelReader) need a file, anyway.
* In addition, the PR reorganizes the source classes to:
* prevent code duplication
* enable lazy loading of file contents.